1. Field of the Invention
The present invention relates to a suction cup.
2. Description of the Related Art
Suction cup is used for the purpose of attaching various objects to surfaces to be adsorbed.
If the surface to be adsorbed is such as having fine irregularity or roughness, typically as found in dashboards of automobiles, any effort of allowing the adsorption surface of the suction cup to adsorb the surface to be adsorbed fails in keeping adhesiveness between the adsorption surface and the surface to be adsorbed, resulting in formation of a gap between the adsorption surface and the surface to be adsorbed. As a consequence, air comes through the gap to reach the adsorption surface, making it difficult to ensure the adhesiveness by the suction cup.
There has been proposed a suction cup, having a main suction cup unit formed using a hard material such as hard rubber or hard synthetic resin, and a soft material such as soft rubber or soft synthetic resin, as being disposed by polymerization on the inner circumferential surface thereof, allowing use of the soft material as the adsorption surface (see Japanese Utility Model Application Publication No. S59-166015).
Even the suction cup using the above-described soft material, however, cannot keep close adhesiveness between the adsorption surface and the surface to be adsorbed, if the surface to be adsorbed has an irregular surface or roughened surface, placing a limit of ensuring adhesiveness of the suction cup.
The present invention was conceived after considering the above-described situation, and an object thereof resides in providing a suction cup advantageous in terms of ensuring the adhesiveness while reducing the cost, even when the surface to be adsorbed has fine irregularity or roughened surface, without degrading the desirable appearance.